5mm Eyepiece for 180x magnification

[Littleguy80]

I keep toying with the idea of getting a 5mm eyepiece to give me the option of 180x mag. I have a 1.5x barlow which gives ~169x magnification with my 8mm BST Starguider. I think 180x is about the maximum that's realistic for my scope. After that exit pupil starts to get too small. I think 180x would be good for planetary, I've read Saturn responds well to higher mags. Also thinking about Lunar and splitting some of the tighter doubles. 

Interested in whether others find 180x a useful magnification and recommendations for 5mm eyepieces. I've thought about the Vixen SLV as it's on offer still though seems quite expensive for an eyepiece that may have limited use due to needing better conditions. Also considering BST Starguider or maybe another ortho as cheaper options. 

All thoughts appreciated

[estwing]

orthos are fine...if you don't mind looking down a straw...

[Star Struck]

I have a Vixen LV5 for sale in the for sale section

gives excellent views

 

[michael.h.f.wilkinson]

I have the Vixen SLV 5mm and it is excellent. Very much like an Ortho in performance, but you do not need to glue your eyeball to the eye lens, due to the very comfortable eye relief. In terms of quality, it is close to my Pentax XW 5 in all aspects except field of view. The SLV is rather lighter, so when I travel by plane I prefer taking the SLV 5 rather than the XW 5

[Piero]

+1 for the Vixen SLV. I also have the 5mm (and the 9mm too). It is a very nice comfortable eyepiece.  

[F15Rules]

It sounds then as if you have a 900mm focal length scope, perhaps an F9 100mm refractor, or F6 150mm reflector?

Leaving aside unhelpful remarks about orthos, which are in fact ideal planetary high power eyepieces (unless you wear glasses to observe, and so need more eye relief, or don't have a mount with drives), offering unbeatable contrast and sharpness across the whole field, you might well consider the Vixen LV/NLV/SLV variants: they are all optically pretty much the same, (however, the LV/NLV 5mm versions have a 45 Deg fov versus the 50deg fov for the newer SLV version) all with good eye relief and, when bought new, very affordable.

You'd pick one up for between c£35-£45 (LV) and c£50-£60 (NLV/SLV), and enjoy 20mm eye relief on all of them.

Both Vixens and orthos would be significantly better than the Starguider, decent EP's though they are.

Good luck with your selection!

Dave

[spaceboy]

I have a 5mm BST which gives me x180 in my 120ED. The more I use these eyepieces the more I'm impressed by them. They are far from perfect but for the money they really do offer you a lot. That said I don't think there is any beating an ortho for sharp, contrasted, clean planetary observing. If you can get on with the rather small eye lens on the 5mm ortho then I would recommend that over any other affordable eyepiece.

[Littleguy80]

Sorry, was forgetting that signature is not always displayed. I have a SkyWatcher 130(FL 900 F7). I already have a BGO 6mm so I know the eye relief on an ortho isn't an issue. 

Thanks for all replies so far. Very helpful! 

[F15Rules]

Ok, so if you already have a BGO 6mm, a BGO 5mm should be more or less parfocal with the 6mm (little or no need to refocus between the two), which is very useful at high powers.

I do think, though, that with any 5mm EP your scope is going to be near it's limit of maximum useful magnification in most UK skies ( except maybe for lunar viewing), so don't be surprised if x150 often gives you better views than the higher x180 from any 5mm?.

Dave

[Littleguy80]

1 minute ago, F15Rules said:

I do think, though, that with any 5mm EP your scope is going to be near it's limit of maximum useful magnification in most UK skies ( except maybe for lunar viewing), so don't be surprised if x150 often gives you better views than the higher x180 from any 5mm?.

I think this was probably the bigger question in my mind. I don't want to get a 5mm EP and then find that it doesn't get used. 

[spaceboy]

There is no denying there are those rare nights where you'd be kicking yourself for not having the max magnification your scope can offer but I can say from experience in a few scopes that I rarely achieve good views using more than x166. Yeh sure I can up the mag and get those flitting moments but it gives me eye strain and headaches.

[Louis D]

I've been using a 5.2mm Pentax XL at that focal length for nearly 20 years, and it is still as sharp as anything else I've tried from edge to edge.  It's sky background is just a tad bit lighter than the XW line, probably owing to newer coatings on the XWs.  I mostly use it to break up globular clusters, split doubles, and for lunar observations.  If you can find one used for around $175, it's a very good deal.

There is the 4.5mm Meade HD-60 which is quite good if you can find a used one for $50 to $60.  The 5mm BST Starguider for £49 from FLO is probably equivalent in views and much easier to acquire in the UK.

Notice I'm recommending long eye relief options because even at 5mm, my 2 diopters of astigmatism still introduce some blur to the image without eyeglasses.

[Littleguy80]

4 minutes ago, Louis D said:

I mostly use it to break up globular clusters

I hadn't thought about Globular Clusters. M13 through my 6mm BGO has been one of my favourite views to date!

[Alfian]

Looking at your signature you have a 2x barlow with a 1.5x detachable nose piece. This in conjunction with your 8mm Starguider will give  the equivalent off 5.33mm @ 168.75x. Would that not be sufficiently useful on a good night?

[Louis D]

If you can see far enough south, try M22 in Sagittarius as well; although I think it never rises above 13 degrees from your latitude.  That's one advantage to living in south central Texas, I can see many more southerly objects than my more northerly cohorts.

[Littleguy80]

1 minute ago, Alfian said:

Would that not be sufficiently useful on a good night?

You may well be right. For the frequency that it's likely to be used, this is probably the smarter option. 

[Littleguy80]

4 minutes ago, Louis D said:

If you can see far enough south, try M22 in Sagittarius as well; although I think it never rises above 13 degrees from your latitude.

It might be a bit low from here but definitely worth trying for  

[Everton]

Hi,

For my Skywatcher Equinox 80mm (fl 500mm) refractor I have a Televue 7mm Nagler type 1 which gives a magnification of about 71x. When used with a Televue 2.5x Powermate I get 175x which I find ideal for looking at the Moon and splitting close doubles like Epsilon Lyrae. I find this magnification is ideal for Saturn. The Nagler has a huge 82 degree AFOV although the eye relief is a little tight, but that's a small price to pay for that spacewalk experience.

[Littleguy80]

Having decided to do the sensible thing and stick with what I have, I spotted the little fella below for sale on ABS. Temptation was too much and today it arrived in the post all the way from Athens, Greece. It's in great condition. 

Just took it out for a quick spin on Jupiter. The first thing that caught my attention was that the eye relief was  noticeably tighter than the 6mm BGO. I don't wear glasses and didn't find this to be a problem. Jupiter looked superb with the GRS on display and Io and Europa in close formation next to the planet. All 4 moons could be seen in the FOV. I felt that the colours were more vivid with more yellows and oranges coming through. For comparison, I tried my 6mm BGO and my 12mm BST Barlowed to both give 150x. The BST, with the wider FOV and longer eye relief, gave a more relaxed view. Not as sharp as the BGO's but still enjoyable. A good option for friends and family to use. The 6mm BGO shared the sharpness and the contrast of the 5mm but not quite the same colour. The 6mm is more well used than the 5mm so I wonder whether this is a sign of wear in the coatings or simply that the eyepiece is due a clean. All testing carried out so far had been without filters so I decided to try a Neodymium filter on the 5mm BGO. I felt that it lost a lot of the colour and detail that the unfiltered view had had so It was quickly removed. The Neodymium filter has generally always enhanced Jupiter with the 6mm so this was a surprising result to me.  

I moved onto the double double near Vega. The 5mm BGO split by th doubles with ease. Lovely contrast and a clear gap between both pairs. The best split of the double double I've had. Really brought a smile to my face!

For £45, I'm very pleased with the latest addition to my collection. Thanks again to everyone for your responses!

[Charic]

.......a bit late for me, but how well does the 8mm and 12mm BST's Barlow on your scope The 5mm BST would  have sat halfway, but Barlowing the 5mm has limited use, though not impossible!

The larger eye lens, fov and eye relief of the BST are more practical for my needs. 

[Littleguy80]

9 hours ago, Charic said:

.......a bit late for me, but how well does the 8mm and 12mm BST's Barlow on your scope The 5mm BST would  have sat halfway, but Barlowing the 5mm has limited use, though not impossible!

The larger eye lens, fov and eye relief of the BST are more practical for my needs. 

They both Barlow well. If I'd had the 12mm BST before the 6mm BGO then I would probably have been content to use the 12mm barlowed. Side by side, the BGO is the stronger performer, in my opinion. Much better contrast and sharpness. My barlow can do 1.5x and 2x. I've tried both with 8mm with reasonable results, not particularly sharp views. The 2x and 8mm is past the limits of practical magnification on my scope. Again, without the BGO's for comparison, I would probably have been happy with the results.

Of course, the 12mm BST with the 2x Barlow gives close to the same effect as 6mm BST, which I know is something you've wanted

[YKSE]

24 minutes ago, Littleguy80 said:

They both Barlow well. If I'd had the 12mm BST before the 6mm BGO then I would probably have been content to use the 12mm barlowed. Side by side, the BGO is the stronger performer, in my opinion. Much better contrast and sharpness. My barlow can do 1.5x and 2x. I've tried both with 8mm with reasonable results, not particularly sharp views. The 2x and 8mm is past the limits of practical magnification on my scope. Again, without the BGO's for comparison, I would probably have been happy with the results.

Of course, the 12mm BST with the 2x Barlow gives close to the same effect as 6mm BST, which I know is something you've wanted

With my short experience with BST 8mm and 12mm, it definitely agrees with your observation, orthos showed much better scatter controll, planetary and doubles are simply better.

[John]

Baader GO's (and Astro Hutech / Fujiyama orthos) show very little scatter. The 6mm BGO was the 1st eyepiece that showed me Sirius B, the Pup star, and thats a stern test of light scatter control.

[Piero]

Very nice orthoscopic and in great conditions!   

[Timebandit]

 

I love a good quality Ortho. IMO the best eyepiece for sharpness for your £ available . In these days of super wide , long eye relief eyepieces which for a quality one can cost a small fortune. The Ortho purity of image really is excellent,  and  not for a lot of money either. I must say though that I am biased as I have a case full of Orthos, mostly BGO's but I make no apologies for that. As I love a good Ortho in my refractor, and they double up nicely for a bit of binoviewing also☺